Following the description in this branch of the condition of Seasonal Affective Disorder, we have explored the use of light in the treatment of depression. Studies carried out by this group over the past decade have demonstrated the efficacy of phototherapy for winter seasonal depressions. Unfortunately, light treatment is not universally effective for all patients with SAD. Phototherapy is also not always convenient to administer. We have therefore been interested in finding pharmacological approaches to the treatment of SAD. The work of Depue and others has identified dopamine as a neurotransmitter of interest in the subset of depressed patients with seasonal affective disorder (SAD). Experimental treatment of depression with dopaminergic agents began as early as thirty years ago. Studies of the biochemical and behavioral effects of dopamine agonists suggest that in a small subgroup of depressed patients, major antidepressant responses may be achieved. In order to test this hypothesis, we have initiated a placebo-controlled double-blind trial of a levodopa/carbidopa combination treatment, which enhances dopamine synthesis, for winter SAD. To date, twelve SAD patients have been studied and the combination of levodopa and carbidopa is showing a trend to being a more effective treatment for SAD than placebo.